Aerial mine



Dec.10,1946. RWBRITTON 2,412,387

AERIAL MINE Filed Dec. 2; 1941 2 Sheets-Sheet 1 INVENTOR Rob 21? Patented Dec. 10, 1946 UNITED SATES This invention relates to the art of aerial defense, and for its general object aims to provide a balloon-carried bomb device capable of being sent aloft either by civilian or military ground crews intothe path of an attacking wave of hostile "planes.

It is a more particular object of the invention to provide an aerial mine of this nature capable 'of being exploded automatically in response to the rise of the mine to a predetermined and selectively variable height.

It is a still further and particular object to provide an aerial mine in which the bomb charge is exploded by the force of impact of an attacking plane. Y

.It is a still further object of the invention, look-- 'ing to the safety of the ground forces; to provide means for exploding the bomb charge in the event of the mine losing altitude as a result of "the escape of gas from the supporting balloon.

Other objects and advantages, with the foregoing, will become apparent in the course of the following detailed description and claims, the invention consisting in the novel construction and in the adaptation and combination of parts heresupporting balloon being deleted.

Fig. 3 is a fragmentary transverse vertical section taken to a scale enlarged from that of Fig. 2 and on line 3-3 of the latter to detail the pressure-controlled trip mechanism for exploding the bomb charge; and

Fig. 4 is a fragmentary longitudinal vertical section detailing the adjustment arrangement by means of which I am enabled to set the bomb for efiecting an operation of the trip mechanism at a selected height. Referring to said drawings, the bomb proper is denoted generally by the numeral 5 and has in its periphery a hanger-lug 6 fitted with a ring 1 throughwhich is received a suspension cable 8 from a balloon 9, the balloon having a governed displacement sufficient to elevate the suspended bomb toa height necessary for the interception of attacking planes.

'1"Th6 bomb part of the mine is or may be of a spherical form carrying a suitable explosive load I0, and is provided centrally with a cylindrical chamber occupying a diametrical position and which is open at one end and at the other end is exposed to the atmosphere by an axial duct, and in' the wall of said chamber at longitudinally spaced intervals are openings H and l2 over which are applied percussion caps 13 and M functional to the explosives Ill. Removably fitted in said bomb chamber is a shell or casing member 15, and formed in the wall of this casing are openings It and I! spaced in correspondencewith the openings II and I2 and held in registration wt h the latter by a set screw l8. Between the registering openingswhich is to say the openings Il-lfi and the openings |2l'lthe casing is divided longitudinally by a diaphragm 20 to define separated cells at opposite ends thereof. Des gnated by 2|, the inner of such cells is supplied with air through a neck extension IE on which is fitted a knurled cap 23 for trapping the admitted air at ground-level pressure; 'The other or outer cell is designated by 22 and is of a variable-pressure nature in that the same is closed only by a protective cover 2d vented as at 24.

In such latter or var able-pressure cell 22 is a spring-loaded firing pin 25 funct onal to the percussion cap l4 and arranged to explode the latter automatically in response to a rise of the aerial mine to a'predetermined height. The spring for the pin is denoted by 26, and as a means for normally holding such spring under compression I employ a catch 21 fulcrumed as at 28 and held in forward latch ng position by a hinged finger 30 abutting the back wall of the c tch at the free end of the latter. Detailed in Fig. 3, it will be seen that said finger is set by lodging its free end in'the notched extremity of one arm 3| of a bellcrank. and the other arm 32 of the bell-crank serves as a trig er and is forked to str ddle a stem 33 having thereon a tripping collar 34. Said stem, which is attached to the diaphragm, finds a slide bearing in a cross-piece 35, and for-adjustment purposes has its root end threaded to work in the threaded bore of a hub attachment 3B of the diaphragm.

It is believed to be clear from the foregoing that theexpansion of the trapped air Within the cell 25 caused by a lessening of the air pressure within the exposed cell 22 as the balloon-carried mine risesto a higher altitude causes the shifting collar 36 to tri the trigger arm 32 and fire the percussion cap M; coincident with the arrival of the bomb at a height predeterminately governed by the adjustment of the stem 33. It will of course be understood that such automatic detonating system may be rendered inoperative 'piration of a predetermined time interval. not illustrated in the drawings, it may be furthe parts is to permit the bombs to be sent aloft in advance of the arrival overhead of an attacking Wave ofhostile planes, in consequence laying a field of aerial mines which, in their release, are regulated as to buoyancy characteristic of th balloons to have the mines occupy aerial levels within which the attacking planes will be expected to operate. Employed in this manner it is obvious that the pressure-differential method of firing the bomb charges is not applicable, and that detonation must be accomplished either contact of the enemy plane with the bomb, or by other suitable means of control. I have illustrated the bombs as having contact-detonating spine processes 3'5 formed thereon, and it would seem as an adjunct to or in lieu of such detonating spines that radio waves might be advantageously employed to actuate receiving sets carried by the aerial mines or, as another form of control, that the mines be equipped with a clock mechanism functioning to detonate the bomb charges upon the ex- While ther mentioned that the efficiency of the mine from the standpoint of direct-contact firing would be augmented by having the suspension ring l bear against a detonating trigger normally held in inoperative positionby a spring arranged to be overpowered by the force of a sudden tug upon the suspension cable 3, such for example as would occur upon Contact of a plane with the balloon Q as distinguished from the suspended bomb.

To here bring out the import of the provision for exploding th aerial mine automatically in response to the latters rise to an adjustable predetermined height, appreciation must be had of the technique of mass bombing as it is now carried out. The procedure, on the part of the attacking force, is to send waves of heavy bombing planes over the target and, customarily, to have these said planes travel a level path ata given altitude for some peIiOcl of time prior to the actual release of the bomb load, the purpose 'of this level flight being to facilitate a sighting of the target by the planes bombardier.

In using the present invention as a defense against this said level-bombing attack, it is only necessary that the ground forces be enabled to determine the altitude of the approaching enemy planes-and this information can be accurately transmitted from a high-altitude observation plane as well as by cross-checking ground instruments-and a multiplicity of the described aerial bombs ar then released, having been first set to thedetermined altitude for their explosion action. Given a large-scale bombing attack by enemy planes, it is, moreover, quite feasible to release a score of the aerial bombs set for one altitude, another score for another altitude, and still other scores of aerial bombs for still another altitude or altitudes, cr ating a barrier of exploding bombs substantially blanketing a given. rangeof altitude lyingin the path of the bombing planes. Itis not intended or necessarily expected that more than a few of the exploding aerial bombs will destroy attacking planes by direct contact, but the flying shrapnel becomes a distinct weapon separate and apart from the concussive force, and is especially effective against enemy personnel. Used either alone or in conjunction with anti-aircraft fire of ground guns, losses of enemy planes can be expected to be quite high with casualties much more severe than has been heretofor experienced, and sufficient in fact to perhaps largely eliminate levelrun bombinga an effective medium of attack, losses considered.

Describing now the structure which is employed for exploding the bomb charge automatically upon a loss of altitude, there is provided within the constant-pressure cell 21 a springvloaded firing pin 40 functional to the percussion cap is and having it spring 4| held under compression by th lip of a bar 62 slidable longitudinally in bearings 33. The bar lies in paralleling relation to a stem M which projects axially of the cell from the rear face of the diaphragm, and formed on the bar is a ratchet tooth 45. Carried by the stem in complement to the ratchet tooth is a pawl it, the arrangement being one in which the pawl tracks freely over the tooth in the expanding forward travel of thediaphragm but abuts the ratchet face to retract the bar and release the firing pin it} in response to acontractive return travel of the diaphragm.

The invention and the manner of its usage is believed to be apparent from the foregoing detailed description of the illustrated embodiment. It is my intention that all forms of construction and variation in detail comingwithin the scope of the hereto annexed claims are to be, considered as comprehended by the invention.

What I claim is:

1. In an aerial mine, and in combination with a balloon adapted to be released at ground level: a ,bomb carried by .the balloon containing an explosive charge and providing mechanism operatively associated with the charge for exploding the latter, said mechanism comprising a normally inactive firing pin supportedin functional relation to the charge, a spring applied as a powering load for the firingpin, displaceable locking means for releasablyholding said spring under a compression set, .meansnormally inactive .to but .movable linto engagement with said locking means for displacing the latter from its spring-holding 'positiomand means governed by atmospheric pressure and made responsive to a rise of the balloon-suspended bomb to lapredeterminedheight for causing the last-named means to act upon the locking means and displace the same from its spring-holding position.

2. In an aerial mine: the combination of a balloon adapted to be released at ground level; and a bomb carried thereby containing an explosive charge and providing mechanism for firing said charge, said firing mechanism comprising a firing pin supported in functional relation to the charge, a spring for powering said pin to "fire the charge, displaceable locking means arranged to engage said spring and releasably hold the sam in a loaded condition, means normally inactive to but movable intoengagement with said locking means for-displacing the latter from its spring-holdingposition, and devices operatively associated with said locking means and made responsive upon a rise of the balloon-carried bomb to a predetermined height above its point of release to displace said locking means from its said spring-holding position'and permit the spring to assert its power in energizing the firing pin.

3. Structure according to claim 2 in which there is provided a second firing mechanism functional to the charge and acting to explode the latter in the event of the bomb rising to a given height short of the elevation required to operate the first-named firing mechanism and then descending a distance less than the extent of rise.

4. In an areial mine, and in combination with a balloon adapted to be released at ground level: a bomb suspended from the balloon and containing an explosive charge; bomb-carried means functional to said charge and made responsive to changing atmospheric pressures for exploding ROBERTA W. BRITTON. 

